Understanding Oronasal Fistulas in Dogs and Cats: Causes, Symptoms, and Treatment By the team at Tribeca Veterinary Dentistry & Oral Surgery

When it comes to your pet’s health, dental issues can affect far more than their mouth. One of the more serious oral conditions we see in dogs and cats is the oronasal fistula (ONF)—an abnormal opening between the mouth and the nasal cavity. This condition can lead to chronic discomfort, infection, and respiratory problems if left untreated, but with proper diagnosis and treatment, most pets recover fully.

What Is an Oronasal Fistula?

An oronasal fistula (also called an oral-nasal fistula) is an abnormal passage that forms between the oral cavity and the nasal passages. In simpler terms, there’s an unintended “hole” connecting your pet’s mouth to their nose. This allows food, water, and bacteria to pass into the nasal cavity, leading to sneezing, nasal discharge, and secondary infections.

Common Causes of Oronasal Fistulas

While any pet can develop an oronasal fistula, it’s most often seen in dogs—particularly small breeds such as Dachshunds, Miniature Schnauzers, and Toy Poodles. In cats, fistulas may result from advanced dental or systemic disease.

Common causes include:

• Advanced periodontal disease: Severe gum and bone loss around teeth, especially the upper canine (fang) tooth, can erode into the nasal cavity.

• Tooth extraction complications: In cases where extraction sites fail to heal properly, a communication may form between the mouth and nose.

• Trauma: Bite wounds or facial injuries can damage bone and soft tissue.

• Foreign objects: Penetrating injuries from sticks or bones.

• Oral or nasal tumors: Cancerous or benign growths may erode the tissues separating these two cavities.

• Congenital defects: Some pets are born with cleft palates or other developmental defects that create similar openings.

Signs and Symptoms

Pets with oronasal fistulas often show subtle but progressive symptoms that may mimic upper respiratory infections. Look out for:

• Chronic sneezing, especially after eating or drinking

• Nasal discharge (clear, cloudy, or bloody) from one side of the nose

• Bad breath (halitosis)

• Difficulty eating or dropping food

• Reverse sneezing or coughing

• Pawing at the face or signs of oral discomfort

In severe cases, you may notice recurrent nasal infections that do not respond to antibiotics. Because these symptoms overlap with other conditions, proper diagnosis by a veterinary dentist is essential.

Diagnosis

Diagnosis typically involves a comprehensive oral and dental examination under anesthesia. During the exam, your veterinary dentist will carefully inspect the oral cavity, probe the suspected area, and may perform dental radiographs (X-rays) or CT imaging to evaluate the extent of bone loss and nasal involvement.

It’s important to identify the underlying cause—whether periodontal disease, trauma, or another issue—so that surgical repair addresses both the defect and the source.

Treatment

Unfortunately, oronasal fistulas do not heal on their own. Because of the constant motion, moisture, and bacterial presence in the mouth, spontaneous closure is highly unlikely.

The treatment of choice is surgical repair, performed by a veterinary dentist or oral surgeon. Surgery involves:

1. Cleaning and debriding the fistula site

2. Creating a healthy tissue flap from nearby gum tissue

3. Closing the defect with precise sutures in multiple layers to ensure a watertight seal

   
   

In some complex or recurrent cases, advanced flap techniques or bone grafting may be needed. Postoperative care includes pain management, antibiotics, soft-food feeding, and careful oral hygiene during healing.

Prognosis

With timely surgical repair and proper aftercare, the prognosis is excellent. Most pets recover fully and return to normal eating and activity within a few weeks. However, if left untreated, oronasal fistulas can lead to chronic nasal infections, sinusitis, and ongoing discomfort.

Prevention

While some causes (like trauma or congenital defects) can’t be prevented, routine dental care can significantly reduce the risk:

• Schedule regular professional dental cleanings

• Brush your pet’s teeth daily with pet-safe toothpaste

• Monitor for early signs of periodontal disease

• Seek veterinary dental care promptly if your pet shows nasal discharge or oral pain

  
  

Expert Veterinary Dental Care in New York City

At Tribeca Veterinary Dentistry & Oral Surgery, our board-certified veterinary dentists and anesthesiologists are experts in diagnosing and repairing oronasal fistulas in dogs and cats. Using advanced imaging, microsurgical techniques, and comprehensive anesthesia monitoring, we ensure your pet receives the safest and most effective care possible.

If your pet is showing signs of an oronasal fistula—or has been referred for specialized dental surgery—contact us today to schedule a consultation.

📍 Tribeca Veterinary Dentistry & Oral Surgery – New York City’s trusted specialists in advanced pet dental and oral care.